Plastic film bags with reclosable fasteners are in widespread use in many industries and the home. The separable and reclosable fastener provides a convenient means for access into the bag and allows the bag to be reused.
Nursing pouches and disposable baby bottle liners provide a convenient way for nursing, working mothers to provide nourishment and sustenance for newborns and growing babies. Current baby bottle liners do not provide a way to safely store breast milk while minimizing the risk of external contamination of the milk, and internal bacterial growth. One such exemplary prior art baby bottle and liner is disclosed in U.S. Pat. No. 5,385,251 (“the '251 patent”). The '251 patent describes a baby bottle liner that provides a reclosable feature at one end of the liner. A serious drawback of this prior art patent involves the risk of contamination of the contents of the liner at the ends of the reclosable fastener and through the fastener itself. The liner of the '251 patent permits contamination by microbes through the sides of the fastener which are open to the environment. Further, the fastener itself permits air and water to enter the inside of the liner and contaminate the contents thereof. Consequently, a nursing mother may be feeding her child breast milk that may be contaminated with microbes which could cause serious gastrointestinal problems for the child.
Further, the prior art does not solve the problem of how to place an airtight, watertight or vacuum tight reclosable string fastener on a liner that is of a size of most liners for baby bottles. Conventional baby bottle liners are generally narrow in width. Hence, placement and sealing of a reclosable fastener onto a liner of narrow width is also a serious problem.
Reclosable fasteners have been the subject of considerable development throughout the years, as is evidenced by the volumes of patents covering these devices. A common reclosable fastener construction consists of a single rib and corresponding groove assembly. The rib terminates into a generally asymmetric arrowhead-shaped, member commonly referred to as the male end of the fastener. The corresponding groove, commonly called the female end of the fastener, ordinarily consists of walls terminating into hooks for grabbing the rib and interlocking the fastener.
This construction offers many advantages, as well as disadvantages. For instance, the fastener elements can be easily and economically manufactured by extrusion methods. The fastener is also securely retained in the closed position to discharge of contents of the bag. The flanges readily open from the outside by applying a separating force on the pull flanges extending from the mouth of the bag. The key disadvantage of the single rib and groove construction is that unless the fastener components have a certain size or stiffness and are manufactured to closely adhere to strict tolerances, the fastener elements are difficult to align and interlock and do not provide an airtight, watertight, or vacuum tight seal.
The above disadvantages have been overcome by constructing a separable fastener with a plurality of interlockable hook-shaped ribs that can be small in size and are composed of a relatively soft and resiliently flexible material that can be aligned and interlocked by simple inward pressure. However, this construction requires at least one of ribs to be hinged to the bag wall to prevent the fastener from opening by internal pressure, yet still does not achieve a vacuum tight seal. Therefore, a first aspect of the present invention is to provide a reclosable fastener having the advantage of multi-rib and groove construction to facilitate alignment and interlocking engagement of fastener elements and which provide a substantially vacuum tight seal.
Another aspect of the present invention is to provide a reclosable fastener which provides ample resistance to internal separating forces without requiring complex structures manufactured into the fastener elements.
A further aspect of the present invention is to provide a substantially flangeless reclosable fastener that is both substantially watertight and airtight and yet small in size, which reduces plastic usage and cost and allows use of watertight reclosable fasteners in relatively small flexible containers.